Turbines

Turbines are Hydraulic Machine which converts Mechanical Energy to Electric Energy. This is done by Water power supplied to the runner by water jets.

Turbines work on the principle of momentum in which the water gives the moment and that helps in moving the shaft for the generation of power.

Turbines are divided into 2 types of Reaction and Impulse Turbine.

Pelton Turbine or Pelton wheel is an impulse turbine in which only kinetic energy is available to start rotating the turbine runner.

The other turbines are Kaplan and Francis which are reaction turbines in which water has not only the kinetic energy but also has pressure energy and thus they can work in a low head situation.

Pelton Turbine requires high head such as more than 40 m. Francis runs at medium heat about 15-40 m whereas Kaplan runs at a low head less than 15 m

Different Types of Turbines

Pelton Turbine is the Tangential flow Turbine whereas Francis is a Radial inward flow Turbine and Kaplan is an Axial flow Turbine.

 Pelton Turbine is a low discharging turbine with less specific speed. The Francis turbine has a medium discharge and medium speed as compared to both and Kaplan has high discharge capacity and high specific speed.

Pelton wheel has an open casing and the runners are not submerged in water and the Tail Race is below the Turbine. In the case of Kaplan and Francis, the Turbine runner blades are submerged fully while working due to close casing.

Types of Turbines

Pelton wheel Turbine has an open casing and thus runs under atmospheric pressure. The Kaplan and Francis Turbine have close casing and thus require and arrangement to discharge water out. This arrangement is called the Draft Tube.